Cold Air System mph

I've seen that by puuting in a cold air system my horsepower would
increase about 7 but will this increase my MPG also or is it like some
performance mods.. better performance but less MPG

 

It depends on who you ask. From those I have talked to and my own
experience, you may gain some gas mileage in the lower powerbands but upon
acceleration, you will definately suck gas.

Broken hearted, I just (temporarily until gas prices become more sane)
restored my OEM intake and resonator and now enjoy much better gas mileage.
With a short ram on my '02 SC2, I was only getting in the low 20's, stock
(except for a K&N drop-in) and not leadfooting it I am getting high 20's
now.

See Lanes site www.evilplastic.com , he is a Saturn mod guru and has a nice
article on peak hp you can squeeze out of the ol' 1.9.

marx404

 

The whole idea of a cold air induction system is to get more volume of air
in the combustion chambers. Cold air is more dense than hot air and makes
for a better charge. This is only a benefit under wide open throttle. Not
sure how the intake air sensor and coolant temp sensors affect this. Most
likely will sense the warm engine and cool intake air then enrich the fuel
mixture slightly.
For economy, a slightly heated intake air will assist fuel vaporization.

 

The car has to maintain an average 14.7:1 Fuel ratio so if you are
getting more air you will get more fuel. One has to keep in mind when
you read the print for these "performance products" they dont say they
"Will give you XX Horse power" they say they can give you "up to" XX
horse power. Key words are "up to".

 

thanks all for the great info.. since I am trying to get the best mpg's
I can get I guess sticking to my system is a must,

97-sl2 autolite 1 hooter range and gapped at 45.. give me 44 hiway and
35 city. I also use mobil 1 religiously

Thanks
again

 

Why gapped at .045?

 

"hooter" range? Hmmmmmmm

 

well because I had a serious increase in MPG. When I installed new
plugs(NGK's) I gappe dthem at .040 per spec and my milage went to pot.
I did have slightly better performance but my hiway miles would only
get to 34 tops. The old plugs were getting me 37 and my city went to
24!!
I kept the old plugs so I checked them.. they were pretty worn but were
a hotter range autolite. I purchased the autolites like the old ones
gapped them at .040 and nothing changed other than they stayed cleaner.
I checked the old plug gap and most were in the .050 range, probably
because of wear but they were still firing. Then figured I would split
the dif and regap the new plugs at .045.. wow instant increase in MPG..
why?? I have no clue but it works for my saturn so what the heck.

 

And, any 'increase' smaller than 20 HP or so is within the realm of
uncertianty for most dynos anyway - they simply can't resolve down that
low. I recall reading somewhere that the more common chassis dynos out
there can't accurately resolve smaller than 10 HP - it's impossible
because of DAC limitations, etc.

One of these days, I'm going to get my hands on 2 good thermocouples*
and measure air temp at ambiant and at the face of the throttle body,
and see what the rise on the *stock* system is. And I suspect it's very
low given plastic conducts heat like shit, and the transit time from
going from the wheelwell intake location to the throttle body is short.
Supporting this is the IAT sensor location on the SC2 - it's burried up
front ahead of the air filter. If they were seeing a big air temp rise,
it'd be a LOT closer to the TB, since any rise isn't really going to be
a known, predictable quantitity.

I figure a TC right at the throttle body's inlet will suffice as a good
IAT spot, and another on the end of the antenna will give a decent
ambient reading, though I'm thinking it'd be more accurate to mount it
up at the nose at the level where the inlet is on the pax side. Since I
want to use the same readout, I'll need to swap the plug between the
two. big whoop.


In other words, my hunch is the big performance gains from so called
'cold air induction' systems are from driving around with lighter
wallet...

*I have access to these plus a readout unit that's known to be pretty
accurate since I use it for industrial calibration all the time, and
it's been checked periodically. I can scounge up two thermocouples easy.

 

Thanks for the explanation. It makes sense to me that a larger spark may
lead to more contact area and better/more complete combustion of the
air/fuel mixture in the cylinder. Our 1996 SL had specified .060" gap in
the owner's manual and on the decal under the hood. But, we learned that
this was later retracted by Saturn and a gap of .040" was suggested instead.

I often wondered if they had increased the gap that year in an effort to
further improve the fuel economy, but found that it caused misfires under
certain conditions. The additional .005" does not sound like a big deal to
me and is probably within the tolerance allowed, but clearly the additional
..02" that they tried to push this did not work. I also agree that as the
electrode fires it gets consumed so the gap will increase over use.

One thing I found on my son's SL is that the spark coil and tower
connections seem to get corroded. Maybe this routine degradation over time
was what was causing the misfires since the wider gap would require
substantially higher voltage to fire. If so and you keep these clean and
make sure your wires are also in good shape the wider gap could lead to
improved fuel economy?

Hey while we are on the subject of spark plugs and the spark gap, the other
thing I never understood was why on the official release that "corrected"
the spark plug gap from .060 to .040 on the 1996 SL documentation, they
specifically said to REPLACE the plugs and not attempt to re-gap them once
they had been used at .060 Given how easy it is to re-gap, I never
comprehended and they never shared the rationale behind that statement.
Other than them selling additional parts and their not being terribly
expensive and possibly needing replacement anyway, the only other thought I
could come up with was that running them with the larger gap somehow
weakened them or made them more likely to fail prematurely at some point
down the road. If anyone has other thoughts let me know ... I know it is
not important, but I always like to learn about the facts behind the
decisions and never had this curiosity satisfied even though it happened
several years back.

Thanks again for sharing your story.

Bob

 

And, any 'increase' smaller than 20 HP or so is within the realm of

Where did you get this info? I've done quite a few runs on a Dynojet dyno
with my 2 cars, and the amount that most people would consider within the
realm of statistical insignificance or dyno error is probably around 3
horsepower. Any difference larger than that does register and is repeatable
(if other factors are the same between runs - coolant temp being the largest
one).

One of the first things I added to my '94 SC2 was an aftermarket air intake.
Simply swapping this out in ten minutes will give you a verified measurable
gain of 7 horsepower on an otherwise stock DOHC. In fact, we have seen cars
on the dyno do more than that, but that's the most common number. My car
club (http://www.saturnperformanceclub.com) dynos a good number of Saturns
frequently, and this is a number that I have witnessed first-hand. This is
not a "hunch", nor is it speculation, rumor, or biased claims from people
selling parts. If there are those here who doubt it, let me know and I will
dig up the dyno runs comparing air intakes from the same car and the same
session.

I can't say I know if an intake has a positive effect on mpg though.

Lane [ lane (at) evilplastic.com ]

 

3HP is the theoretical. Guess what - ADCs aren't repeatable and linear
down that low, and op amps aren't that stable. You're talking about a
flip of the least significant bit and the next one up. Most ADCs simply
aren't that accurate, and the ones that are varen't that cheap. in any
case, the same applies to all the analog stuff leading to the ADC.
Practically, anything under 3X that could EASILY be attributed to
quantization error and drift in the analog section of the electronics.
So, that's 9HP, I was off a bit.

See above. The dyno's analog section and ADCs drifting can give you
7hp. And thermal drift is a huge question mark even after the
electronics have stabalized.

Sure you'll see a different dyno chart. But that's not because of some
'cold air induction' effect, it's because the different length intake
pipes do all sorts of fun things acoustically. You're seeing an
*acoustic* effect, not a thermal one. Intakes, like exhausts, are
acoustic beasts, that's why there's that funky box on the stock pipe
right neat the bend to the TB.

You want to prove a CAI actually is worth the box it came in, i.e. that
it's actually bringing colder air into the engine, show some
thermocouple - not a crappy thermistor - instrumented tests showing the
air temperatures at the throttle body inlet Vs ambiant conditions Vs
what a stock intake's doing.

And I bet you you'll find that the difference in temperature between
where the air's being sucked into the car in the front right corner by
the turn signal, Vs the air temp at the throttle body on a stock intake
setup is within 1 or 2 degrees, tops. And I doubt it's even that much
at highway speeds - the time it takes the air to get sucked in, pass
accross the to the airbox, go up to the TB is likely under 1 second -
I'm sure it can be roughly calculated.

 

I dont know where you're getting these idea's at but let me clearify
what you should and should not do. DO NOT run plugs of a different Heat
range than that specified by Saturn! They are smart engineers, you are
not. Do not run anything other than Double Platinum Plugs as it is a
"waste spark system" (autolite and ac-delco are good). Do NOT regap
platinum plugs, the plugs for that engine should already have a .040"
gap. S-series saturns use a Compression sense ignition system. If you're
spark plug wires are to high in resistance you will have problems.

Low resistance wires (less than 10k ohms) and double platinum plugs is
all you should need.

Plugs for a 97 DOHC Saturn:
Autolite Ignition APP3926 Gap .040 $3.97each

I think it has to do with compression sense. They probably had to many
"cam sensor" codes and "quad driver" codes being thrown or something. I
think it could of been avoided with low resistance spark wires. Platinum
actually increases the resistance which doesnt work well with poor wires
or weak ignition coils.

 

FYI - my post pertained to a generic aftermarket intake that does not
relocate the air inlet outside of the engine compartment. The results I've
seen on the dyno charts from these have been very favorable.

I can't say I know much about digital circuits and can see that you are
proud of your knowledge there. But before you claim that dyno results of
7 - 9 hp difference mean nothing because of limitations in the componentry
of the measuring equipment, please do some research on specific dyno
equipment & software. And maybe ask the question of their tech support
departments. I would be AMAZED AND DUMBFOUNDED if their hardware/software
was subject to errors like that. Don't forget to report back to the group
with findings because I am very interested.

Lane [ lane (at) evilplastic.com ]

 

I have been at the same dyno sessions Lane has. We have not only gone
from stock to aftermarket, we've gone from aftermarket to stock. And
every time, we see repeatable numbers.

And as far as accurate parts not being cheap, dynos are most definatly
NOT cheap. and getting them calibrated isn't cheap either. TMW Chassis
Dyno, where we go, does keep their dyno calibrated, and well maintained.

 

well if a standard plug heat range is to cover all situations as saturn
engineers would do in order to give ALL AROUND best performance and
milage how about the people that are in stop and go traffic and seldom
get on the hiway.. the plug manufacturers would suggest a plug in the
next heat range especially with our good old saturn oil burners.

The other thing I don't understand is everywhere you look you see DON'T
USE PLATIMUMs in a saturn for the will give you grief down the pike.
The reasoning behind it as far as I have read is becasue the platinum
plug burn hotter!! go figure.. I would rathe replace a 1.15 autolight
plug if they start to act up but so far 20k miles on these and they are
fine.

 

Check and Clean PVC
Thats a common source of oil consumption.

Still Fouling plugs?
Decarbonize engine.

Thus they burn off oil deposites and stay cleaner longer... :-\

I would rathe replace a 1.15 autolight

1.15 autolight Regular plugs replace every 20-30k
3.97 autolight Platinum plugs replace every 80-100k

Which is cheaper, especially in the long run if you pay to have them put
in?

 

I havent really been reading the thread closely but i concur on the
don't use platinum guy. I tried them twice in a row and had EGR valves
go bad each time. Replaced them with standards and never had the
problem again.